Irrelevant under these circumstances. Craig did not make an Alford plea (and courts are increasingly reluctant to allow them). You have to explicitly make an Alford plea for it to be effective.
I haven't read a transcript of the guilty plea so I don't know of the relevance. Regardless, I was commenting on your assertion that "A guilty plea generally removes all possible doubt".
I rarely have seen a judge refuse to accept an Alford plea. Also, I don't know what you mean by "explicitly", but you can make an Alford plea without ever mentioning you're making an "Alford plea". If you tell the judge that you believe you are innocent but want to plead guilty because you acknowledge that if you went to trial there is a good likelihood that you could be found guilty, you have made an Alford plea.